/**
 * Software License, Version 1.0
 * 
 * Copyright 2003 The Trustees of Indiana University.  All rights reserved.
 * 
 *
 *Redistribution and use in source and binary forms, with or without 
 *modification, are permitted provided that the following conditions are met:
 *
 *1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license;
 *2) All redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the disclaimer listed in this license in
 * the documentation and/or other materials provided with the distribution;
 *3) Any documentation included with all redistributions must include the 
 * following acknowledgement:
 *
 *"This product includes software developed by the Community Grids Lab. For 
 * further information contact the Community Grids Lab at 
 * http://communitygrids.iu.edu/."
 *
 * Alternatively, this acknowledgement may appear in the software itself, and 
 * wherever such third-party acknowledgments normally appear.
 * 
 *4) The name Indiana University or Community Grids Lab or NaradaBrokering, 
 * shall not be used to endorse or promote products derived from this software 
 * without prior written permission from Indiana University.  For written 
 * permission, please contact the Advanced Research and Technology Institute 
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202.
 *5) Products derived from this software may not be called NaradaBrokering, 
 * nor may Indiana University or Community Grids Lab or NaradaBrokering appear
 * in their name, without prior written permission of ARTI.
 * 
 *
 * Indiana University provides no reassurances that the source code provided 
 * does not infringe the patent or any other intellectual property rights of 
 * any other entity.  Indiana University disclaims any liability to any 
 * recipient for claims brought by any other entity based on infringement of 
 * intellectual property rights or otherwise.  
 *
 *LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO 
 *WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 *NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF 
 *INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS. 
 *INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS", 
 *"VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.  
 *LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR 
 *ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION 
 *GENERATED USING SOFTWARE.
 */
package cgl.narada.jms;

import java.util.StringTokenizer;


/**
   There could be multiple sessions registered to a given connection. When an 
   event is received we need to make sure that event is routed only to the 
   appropriate sessions. Furthermore, there exist multiple subscribers, 
   possibly, on any given session. The session has thus to ensure that the 
   event is routed to appropriate subscribers. Once the event is received at 
   a subscriber, it needs to be routed to its appropriate message listener. 
   
   @author Shrideep Pallickara
   $Revision$
   $Date$
*/

public class JmsReceivedEventDistributor {
  
  public static boolean matchesSessionTopic(String topicInEvent, 
					    String sessionTopic) {
    if (topicInEvent.equals(sessionTopic)) 
      return true;
    
    /** The topic of published event could Scores=NBA, Team=NYK the session 
	could registered only for Scores=NBA which should be fine */
    if (topicInEvent.length() < sessionTopic.length())
      return false;
    
    StringTokenizer eventTopicTok = new StringTokenizer(topicInEvent, ",");
    StringTokenizer sessionTopicTok = new StringTokenizer(sessionTopic, ",");
    
    int eventTokens = eventTopicTok.countTokens();
    int sessionTokens = sessionTopicTok.countTokens();
    
    if (sessionTokens > eventTokens)
      return false;
    
    for (int i=0; i < sessionTokens; i++) {
      if (!eventTopicTok.nextToken().equals(sessionTopicTok.nextToken()))
	return false;
    }/*end-for */
    
    return true;
  }
  
  public static boolean matchesSpecifiedSelector(String topicInEvent,
						 String messageSelector) {
    if (topicInEvent.equals(messageSelector)) 
      return true;
    
    /** We need to be absolutely sure that the event matches the selector.
	We don't want this event to be routed to the wrong topic subscriber */
    StringTokenizer eventTopicTok = new StringTokenizer(topicInEvent, ",");
    StringTokenizer msgSelTok = new StringTokenizer(messageSelector,",");
    
    int eventTVpair = eventTopicTok.countTokens();
    int selTVpair = msgSelTok.countTokens();
    int tagValuesToMatch=0;
    
    /** If the selctor has greater number of tags, the event doesn't obviously
	satisfy the imposed selector constraints */
    if (eventTVpair >= selTVpair)
      tagValuesToMatch = selTVpair;
    else 
      return false;
    
    /** We now proceed to match individual tag-value pairs. */
    for (int i=0; i <tagValuesToMatch; i++) {
      StringTokenizer eventTVTok = 
	new StringTokenizer(eventTopicTok.nextToken(), "=");
      StringTokenizer selTVTok = 
	new StringTokenizer(msgSelTok.nextToken(), "=");
      
      
      if (!eventTVTok.nextToken().equals(selTVTok.nextToken() ))
	return false;

      String topicVal = eventTVTok.nextToken();
      String selVal = selTVTok.nextToken();
      
      if (! (topicVal.equals(selVal) || selVal.equals("*")) )
	return false;
    } /*end-for*/
    return true;
  }/*end-method */
  
}
